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Peptide Interaction Checker

Pick two or more peptides or medicines. For every pair you get what is actually known, how strong the evidence is, and the sources, including the pairs where the honest answer is that nobody has studied them.

Short answer: the clearest interactions here come from FDA labels: don't stack two GLP-1 medicines, expect a higher low blood sugar risk when semaglutide or tirzepatide is added to insulin or a sulfonylurea, and on tirzepatide add a backup to birth control pills for 4 weeks at the start and after each dose increase. For most research peptides, such as BPC-157 or TB-500, no human study of any combination exists.

Education only, not medical advice. "No known interaction" means we found nothing reported, not that a combination is safe. Most of the peptides here are not FDA approved, and most pairs have never been studied together in people. Talk to your clinician or pharmacist before you start, stop or combine anything. Runs in your browser; nothing you pick is sent anywhere. Last reviewed October 22, 2026.

How each pair is rated

Every pair gets two labels: what the evidence says to do, and how strong that evidence is. They are separate on purpose. A "no known interaction" built on zero studies is not the same as one built on an FDA drug study.

Avoid. An FDA label or strong evidence says not to combine these, or they duplicate the same treatment.
Caution. There is a documented or likely risk to watch for, such as low blood sugar or added side effects. Talk to your prescriber before combining.
Same pathway. Both act on the same receptor or hormone pathway, so stacking them overlaps. No specific harm from the pair has been documented.
No known interaction. Nothing reported. For most peptides that is because the pair was never studied, so it means unknown, not safe.

FDA label (11 pairs). The interaction is described in the FDA-approved prescribing information for at least one of the two.
Human study (2 pairs). At least one published study in people speaks to this pair.
Animal study (2 pairs). The only direct evidence comes from animal or lab studies, which often do not carry over to people.
Mechanism only (23 pairs). Theoretical. No study tested the pair; the concern comes from documented effects of each compound on its own.
No human studies found (33 pairs). We found no study of this pair in people and no specific reason to expect the two to interact. Each compound's own risks still apply.

How we checked

Each pair started from the Dose Track app's interaction list. For every pair we searched PubMed, FDA labels on DailyMed, FDA web pages and ClinicalTrials.gov, opened each source we cite, and rewrote the text to say only what those sources say. Where nobody has studied the pair, we say so and cite what is documented about each compound on its own. Dosing and timing advice was removed. Pairs we could not support were left out.

All 71 reviewed pairs

Most serious first. Pairs not listed here have no reviewed entry yet.

AvoidFDA label

Semaglutide and Retatrutide

Don't combine: retatrutide is a GLP-1 agonist, and semaglutide's label advises against any other. Retatrutide acts on GLP-1, GIP and glucagon receptors, so it overlaps with semaglutide at the GLP-1 receptor. The Wegovy label says use with any other GLP-1 receptor agonist is not recommended. Retatrutide is investigational, and the two have not been studied together.

Sources (3)

AvoidFDA label

Semaglutide and Tirzepatide

FDA labels say not to combine: tirzepatide shouldn't be used with any GLP-1 drug like semaglutide. Both drugs act on the GLP-1 receptor. The Wegovy label says use with any other GLP-1 receptor agonist is not recommended, and the Zepbound label says the same about tirzepatide with any GLP-1 receptor agonist. Combining them has not been studied.

Read the full Semaglutide and Tirzepatide page

Sources (2)

AvoidFDA label

Tirzepatide and Retatrutide

Don't combine: both act on GLP-1 and GIP receptors, and tirzepatide's label advises against other GLP-1 drugs. Tirzepatide acts on GIP and GLP-1 receptors; retatrutide acts on those two plus the glucagon receptor. The Zepbound label says tirzepatide should not be combined with any GLP-1 receptor agonist. Retatrutide is investigational, and the two have not been studied together.

Sources (2)

CautionMechanism only

CJC-1295 and GHRP-2

GHRH plus GHRP-2 releases more GH than either alone in men; this exact pair is unstudied. No human studies of CJC-1295 with GHRP-2 were found. Giving GHRH and GHRP-2 together produced marked synergistic GH release in 47 men. GHRP-2 also raises prolactin, ACTH and cortisol, and a larger GH effect means more chance of GH-related effects such as higher blood sugar.

Sources (3)

CautionMechanism only

CJC-1295 and GHRP-6

GHRH plus GHRP-6 releases more GH than either alone; GHRP-6 can also raise cortisol and prolactin. No human studies of CJC-1295 with GHRP-6 were found. In healthy men, natural GHRH plus GHRP-6 released more GH than either alone, and at higher GHRP-6 doses prolactin and cortisol about doubled. A larger GH effect also means more chance of GH-related effects such as higher blood sugar.

Sources (3)

CautionMechanism only

CJC-1295 and Hexarelin

GHRH plus hexarelin releases more GH than either alone; hexarelin's effect fades with repeated use. No human studies of CJC-1295 with hexarelin were found. In healthy men, GHRH(1-29) plus hexarelin released more GH than either alone. Hexarelin also raises prolactin, ACTH and cortisol, and its GH effect fell by about half within a week of regular use in children.

Sources (3)

CautionMechanism only

CJC-1295 and Ipamorelin

Different GH pathways that boost each other; this exact pair has not been studied in humans. No human studies of these two together were found. In human studies, a GHRH-type drug plus a GHRP-type drug released more GH than either alone. CJC-1295 is a GHRH analog and ipamorelin is a GHRP-type drug, so a larger GH effect than either alone is expected.

Sources (3)

CautionMechanism only

IGF-1 LR3 and CJC-1295

Both raise IGF-1 activity; IGF-1 can lower blood sugar. No human data on IGF-1 LR3. No human studies of these two together were found. IGF-1 LR3 has no published human studies. CJC-1295 raises the body's own IGF-1, and the approved IGF-1 drug (mecasermin) is labeled for causing low blood sugar. The effects of long-term high IGF-1 in people are not known.

Read the full IGF-1 LR3 and CJC-1295 page

Sources (3)

CautionMechanism only

IGF-1 LR3 and Ipamorelin

Ipamorelin raises GH (and so IGF-1); IGF-1 can lower blood sugar. No human data on IGF-1 LR3. No human studies of these two together were found. IGF-1 LR3 has no published human studies. Ipamorelin raises GH, which drives IGF-1. The approved IGF-1 drug (mecasermin) is labeled for causing low blood sugar, and the GHRH analog tesamorelin is labeled for swelling and joint pain from fluid retention and for unknown effects of long-term high IGF-1.

Sources (3)

CautionMechanism only

Ipamorelin and Sermorelin

GHRH-type plus GHRP-type drugs boost GH together; this exact pair is unstudied. No human studies of these two together were found. Sermorelin is a GHRH analog and ipamorelin acts on the GHRP (ghrelin) receptor. In human studies, GHRH plus a GHRP-type drug released more GH than either alone, so a larger GH effect, and more GH-related effects like higher blood sugar, would be expected.

Sources (3)

CautionMechanism only

Melanotan II and PT-141

Same receptor family: PT-141 is an analog of melanotan II, so side effects may stack. PT-141 (bremelanotide) was developed as an analog of melanotan II, and both act on melanocortin receptors. No studies of the two together were found. PT-141 commonly causes nausea, briefly raises blood pressure and can darken skin; adding a second drug on the same receptors may add to these effects.

Sources (3)

CautionMechanism only

MK-677 and CJC-1295

Both raise GH and IGF-1; MK-677 alone raised blood sugar and caused swelling in a trial. No human studies of these two together were found. Both raise growth hormone and IGF-1 through different routes, so effects may add. In a 2-year trial, MK-677 alone raised fasting blood sugar, lowered insulin sensitivity and caused mild leg swelling and more appetite.

Sources (3)

CautionMechanism only

MK-677 and Semaglutide

Likely work against each other: MK-677 raised appetite and blood sugar in a trial. No human studies of these two together were found. In a 2-year trial in older adults, MK-677 increased appetite, body weight and fasting blood sugar and reduced insulin sensitivity. Semaglutide lowers appetite and blood sugar, so MK-677 may blunt its effects.

Sources (2)

CautionMechanism only

PT-141 and CJC-1295

No combination studies; both have documented effects on heart rate or blood pressure. No human studies of these two together were found. The Vyleesi (PT-141) label says each dose briefly raises blood pressure and lowers heart rate. The FDA says it has identified serious adverse events with CJC-1295, including increased heart rate and a widespread blood-vessel-widening reaction. Whether these effects add up or offset each other has not been studied; people with heart disease or high blood pressure should be cautious.

Read the full PT-141 and CJC-1295 page

Sources (3)

CautionMechanism only

PT-141 and Semaglutide

No studies together; both can cause nausea and both slow stomach emptying. No human studies of these two together were found. PT-141 (bremelanotide, Vyleesi) commonly causes nausea and may slow stomach emptying; semaglutide does both too. Together they could add up, and both labels warn that slower stomach emptying can change how oral medicines work.

Sources (2)

CautionMechanism only

Retatrutide and CJC-1295

No human studies together; GH-raising drugs can raise blood sugar while retatrutide lowers it. No human studies of these two together were found. CJC-1295 raises growth hormone, and the growth hormone (somatropin) label says GH can lower insulin sensitivity and unmask high blood sugar or diabetes. Retatrutide lowers blood sugar. The two push glucose in opposite directions, so blood sugar may be harder to predict; this is a theoretical concern, not a measured one.

Read the full Retatrutide and CJC-1295 page

Sources (3)

CautionHuman study

Semaglutide and Cagrilintide

Tested together as CagriSema, an investigational fixed combination; most users had stomach side effects. Cagrilintide plus semaglutide (CagriSema) has been tested in large trials as a single investigational product, not as a do-it-yourself stack. In the phase 3 REDEFINE 1 trial, average weight loss was 20.4% at 68 weeks vs 3.0% on placebo. Gastrointestinal side effects affected 79.6% vs 39.9% on placebo, mostly mild to moderate and temporary.

Read the full Semaglutide and Cagrilintide page

Sources (2)

CautionMechanism only

Semaglutide and CJC-1295

No human studies together; GH-raising drugs can raise blood sugar while semaglutide lowers it. No human studies of these two together were found. CJC-1295 raises growth hormone, and the growth hormone (somatropin) label says GH can lower insulin sensitivity and unmask high blood sugar or diabetes. Semaglutide lowers blood sugar. The two push glucose in opposite directions, so blood sugar may be harder to predict; this is a theoretical concern, not a measured one.

Read the full Semaglutide and CJC-1295 page

Sources (3)

CautionFDA label

Semaglutide and Insulin

Low blood sugar risk goes up; the label says to consider lowering the insulin dose. Semaglutide lowers blood sugar. The Ozempic and Wegovy labels say the risk of low blood sugar, including severe low blood sugar, is higher when semaglutide is used with insulin, and that prescribers should consider reducing the insulin dose when semaglutide is started. The Wegovy label adds that adding Wegovy to insulin has not been studied.

Read the full Semaglutide and Insulin page

Sources (2)

CautionFDA label

Semaglutide and Oral medications (pills)

Semaglutide slows stomach emptying, which may change how pills are absorbed. Semaglutide delays stomach emptying, so the labels say it may affect the absorption of medicines taken by mouth. In the drug studies in the label, injected semaglutide did not change absorption of the tested pills to a clinically relevant degree. The Wegovy label notes levothyroxine exposure rose 33% with the semaglutide tablet and advises closer monitoring for pills with a narrow safety margin.

Read the full Semaglutide and Oral medications (pills) page

Sources (2)

CautionFDA label

Semaglutide and Sulfonylureas

Low blood sugar risk goes up; the label says to consider lowering the sulfonylurea dose. Sulfonylureas such as glipizide, glyburide and glimepiride make the pancreas release more insulin. The Ozempic and Wegovy labels say semaglutide with a sulfonylurea raises the risk of low blood sugar, including severe low blood sugar, and that prescribers should consider reducing the sulfonylurea dose when semaglutide is started.

Sources (2)

CautionMechanism only

Sermorelin and GHRP-2

GHRH plus GHRP-2 boosts GH release in men; GHRP-2 also raises cortisol and prolactin. Giving GHRH and GHRP-2 together produced marked synergistic GH release in 47 men (natural GHRH, not sermorelin itself). A small chart review of men taking sermorelin with GHRP-2 and GHRP-6 found higher IGF-1, but had no control group. GHRP-2 raises prolactin, ACTH and cortisol.

Sources (3)

CautionMechanism only

Sermorelin and GHRP-6

GHRH plus GHRP-6 boosts GH release in men; GHRP-6 can raise cortisol, prolactin and blood sugar. In healthy men, GHRH plus GHRP-6 released more GH than either alone, and at higher GHRP-6 doses prolactin and cortisol about doubled. A small chart review of men taking sermorelin with GHRP-6 and GHRP-2 found higher IGF-1, with no control group.

Sources (3)

CautionHuman study

Sermorelin and Hexarelin

GHRH(1-29) plus hexarelin released more GH than either alone in men; hexarelin's effect fades with use. In 7 healthy men, a single dose of GHRH(1-29) plus hexarelin released more GH than either alone; sermorelin is a 29-amino-acid GHRH analog. Hexarelin's GH effect dropped by about half within a week of regular use in children.

Sources (3)

CautionFDA label

Tirzepatide and Birth control pills

The label says to switch to a non-pill method or add a barrier method for 4 weeks at the start and after each dose increase. The Mounjaro and Zepbound labels tell people on birth control pills to switch to a non-oral method, or add a barrier method such as condoms, for 4 weeks after starting tirzepatide and for 4 weeks after each dose increase. Hormonal birth control that is not taken by mouth, such as an implant, IUD, ring or shot, should not be affected.

Sources (2)

CautionMechanism only

Tirzepatide and CJC-1295

No human studies together; GH-raising drugs can raise blood sugar while tirzepatide lowers it. No human studies of these two together were found. CJC-1295 raises growth hormone, and the growth hormone (somatropin) label says GH can lower insulin sensitivity and unmask high blood sugar or diabetes. Tirzepatide lowers blood sugar. The two push glucose in opposite directions, so blood sugar may be harder to predict; this is a theoretical concern, not a measured one.

Read the full Tirzepatide and CJC-1295 page

Sources (3)

CautionFDA label

Tirzepatide and Insulin

Low blood sugar risk goes up; the label says to consider lowering the insulin dose. Tirzepatide lowers blood sugar. The Mounjaro and Zepbound labels say that when tirzepatide is started, prescribers should consider reducing the dose of insulin to lower the risk of low blood sugar.

Sources (2)

CautionFDA label

Tirzepatide and Oral medications (pills)

Tirzepatide slows stomach emptying, which may change how pills are absorbed. Tirzepatide delays stomach emptying, so the labels say it may affect the absorption of medicines taken by mouth and advise caution. They specifically advise monitoring people on pills that need to stay above a set level to work, or that have a narrow safety margin, such as warfarin.

Sources (2)

CautionFDA label

Tirzepatide and Sulfonylureas

Low blood sugar risk goes up; the label says to consider lowering the sulfonylurea dose. Sulfonylureas such as glipizide, glyburide and glimepiride make the pancreas release more insulin. The Mounjaro and Zepbound labels say prescribers should consider reducing the sulfonylurea dose when tirzepatide is started, to lower the risk of low blood sugar.

Sources (2)

Same pathwayMechanism only

CJC-1295 and Sermorelin

Both act like GHRH on the same pituitary receptor; no studies of using them together. No human studies of these two together were found. CJC-1295 and sermorelin are both versions of GHRH, the body's own signal for GH release, so they work the same way. Adding one to the other is not known to add benefit.

Sources (2)

Same pathwayMechanism only

GHRP-2 and GHRP-6

Both act on the same ghrelin receptor; stacking is not shown to add GH. No human studies of these two together were found. Both drugs work through the ghrelin (GHRP) receptor, and when two drugs on this receptor were combined in men, GH did not rise further. GHRP-2 raises prolactin, ACTH and cortisol in people, and FDA cites cortisol and blood sugar concerns for GHRP-6.

Sources (3)

Same pathwayMechanism only

Hexarelin and Ipamorelin

Both act on the same ghrelin receptor; hexarelin also raises cortisol and prolactin. No human studies of these two together were found. Both work through the ghrelin (GHRP) receptor, and combining two drugs on this receptor did not add GH in a human study. Hexarelin raises prolactin, ACTH and cortisol in people.

Sources (3)

Same pathwayMechanism only

HGH Fragment 176-191 and AOD-9604

Largely the same compound: AOD-9604 is a modified end-fragment of growth hormone. AOD-9604 is described as a C-terminal fragment of human growth hormone (Tyr-hGH177-191), which overlaps with what is sold as HGH Fragment 176-191. Using both is likely redundant. No studies of the two together were found.

Sources (2)

Same pathwayMechanism only

Ipamorelin and GHRP-2

Both act on the same ghrelin receptor; stacking them is not shown to add GH. No human studies of these two together were found. Ipamorelin and GHRP-2 both work through the ghrelin (GHRP) receptor. When two drugs on this receptor (ghrelin and hexarelin) were given together in men, GH did not rise further. GHRP-2 raises prolactin, ACTH and cortisol in people.

Sources (3)

Same pathwayMechanism only

MK-677 and Ipamorelin

Both act on the ghrelin receptor; MK-677 alone raised blood sugar and caused swelling in a trial. No human studies of these two together were found. MK-677 and ipamorelin both work through the ghrelin (GHRP) receptor, and stacking two drugs on this receptor did not add GH in a human study. MK-677 alone raised fasting blood sugar, lowered insulin sensitivity and caused mild leg swelling.

Sources (3)

No known interactionNo human studies found

5-Amino-1MQ and Semaglutide

No studies of 5-Amino-1MQ with semaglutide; 5-Amino-1MQ has no human trials found. No human studies of these two together were found. 5-Amino-1MQ blocks the NNMT enzyme and reduced weight in obese mice, but no human studies were found. Semaglutide's label notes it slows stomach emptying, which can affect oral medicines.

Sources (3)

No known interactionAnimal study

BPC-157 and CJC-1295

No human studies of this pair; one lab study links BPC-157 to GH signaling in rat tendon cells. No human studies of these two together were found. In rat tendon cells, BPC-157 raised growth hormone receptor levels, which made the cells respond more to GH. Whether this happens in people, or matters for healing, has not been tested. No known interaction reported.

Sources (3)

No known interactionNo human studies found

BPC-157 and GHK-Cu

BPC-157 and GHK-Cu work differently, but no studies tested them together. No human studies of these two together were found. GHK-Cu is a copper peptide that raises collagen and supports skin repair in lab and animal work, and is used on the skin. BPC-157's healing effects come mostly from animal studies. They act through different mechanisms; no known interaction has been reported.

Sources (3)

No known interactionNo human studies found

BPC-157 and HGH Fragment 176-191

No studies of BPC-157 with HGH Fragment 176-191; human data on each are very limited. No human studies of these two together were found. BPC-157's human evidence is three small, poor-quality studies. HGH Fragment 176-191 is closely related to AOD-9604, a lab-made piece of growth hormone studied for fat loss mainly in animals. No known interaction has been reported.

Sources (3)

No known interactionAnimal study

BPC-157 and Ipamorelin

No human studies of this pair; healing benefit of combining them is untested. No human studies of these two together were found. In rat tendon cells, BPC-157 raised growth hormone receptor levels, so GH had a larger effect on cell growth. That has not been tested in people. No known interaction reported.

Sources (3)

No known interactionNo human studies found

BPC-157 and KPV

BPC-157 and KPV both reduce gut inflammation in animals; no studies tested them together. No human studies of these two together were found. KPV, a three-amino-acid peptide, reduced colitis in mice and blocked the NF-kB inflammation pathway in cells. BPC-157 is a stomach-derived peptide studied mostly in animals. The FDA says it has no human exposure data for KPV. No known interaction has been reported.

Sources (3)

No known interactionNo human studies found

BPC-157 and PT-141

No studies of BPC-157 with PT-141 (bremelanotide); no known interaction reported. No human studies of these two together were found. PT-141 is the FDA-approved drug bremelanotide (Vyleesi), approved only for low sexual desire in premenopausal women. BPC-157 is not approved and has very little human data. No known interaction has been reported.

Sources (2)

No known interactionNo human studies found

BPC-157 and Retatrutide

No studies of BPC-157 with retatrutide; both are unapproved. No human studies of these two together were found. Retatrutide is an investigational drug still in trials, and BPC-157 is not FDA-approved; the FDA says it has little or no safety data for BPC-157. There is no evidence that BPC-157 reduces retatrutide's stomach side effects.

Sources (2)

No known interactionNo human studies found

BPC-157 and Semaglutide

No studies of BPC-157 with semaglutide; no known interaction reported. No human studies of these two together were found. BPC-157 is not FDA-approved, and the FDA says it has little or no safety data for it. There is no human evidence that BPC-157 reduces nausea or other stomach side effects of semaglutide.

Sources (2)

No known interactionNo human studies found

BPC-157 and Semax

No studies of BPC-157 with Semax; no known interaction reported. No human studies of these two together were found. Semax has been studied in Russian clinical trials, such as stroke rehabilitation; BPC-157's human data are three small, poor-quality studies. The FDA says it has limited or no safety information for either compound by the routes people use. No known interaction has been reported.

Sources (3)

No known interactionNo human studies found

BPC-157 and TB-500

No studies tested BPC-157 and TB-500 together; both have almost no human data. No human studies of these two together were found. BPC-157's healing effects come mostly from animal studies; human data are three small, poor-quality studies. The FDA says it has found no human exposure data for TB-500 (a thymosin beta-4 fragment). No known interaction has been reported, but that reflects missing research, not proof of safety.

Read the full BPC-157 and TB-500 page

Sources (3)

No known interactionNo human studies found

BPC-157 and Thymosin alpha-1

No studies of BPC-157 with thymosin alpha-1; no known interaction reported. No human studies of these two together were found. Thymosin alpha-1 has been tested in human trials, for example in chronic hepatitis B, though a 2026 Cochrane review rated that evidence low to very low certainty. BPC-157 has very little human data. No known interaction has been reported.

Sources (3)

No known interactionNo human studies found

BPC-157 and Tirzepatide

No studies of BPC-157 with tirzepatide; no known interaction reported. No human studies of these two together were found. BPC-157 is not FDA-approved, and the FDA says it has little or no safety data for it. There is no human evidence that BPC-157 eases tirzepatide's stomach side effects.

Sources (2)

No known interactionNo human studies found

CJC-1295 and HGH Fragment 176-191

No studies of this pair; the claim that high GH blunts the fragment is unsupported. No human studies of these two together were found. HGH Fragment 176-191 (sold as AOD-9604) is a piece of the GH molecule studied for fat loss mainly in mice. Nothing published shows that raising your own GH makes it work less. No known interaction reported.

Sources (2)

No known interactionNo human studies found

DSIP and CJC-1295

No studies of DSIP with CJC-1295 were found; no known interaction reported. No human studies of these two together were found. DSIP had weak effects on sleep in a small controlled trial in people with insomnia. No known interaction reported.

Sources (2)

No known interactionNo human studies found

DSIP and Ipamorelin

No studies of DSIP with ipamorelin were found; no known interaction reported. No human studies of these two together were found. DSIP's own sleep effects in people were weak in a small controlled trial. No known interaction reported.

Sources (2)

No known interactionNo human studies found

Epitalon and BPC-157

No studies of epitalon with BPC-157; both have very little human data. No human studies of these two together were found. Epitalon's telomere effect comes from lab cell studies; BPC-157's human data are three small, poor-quality studies. The FDA says it has not identified safety information on epitalon for its proposed route. No known interaction has been reported.

Sources (3)

No known interactionNo human studies found

Epitalon and CJC-1295

No studies of epitalon with CJC-1295; no known interaction reported. No human studies of these two together were found. CJC-1295 raises growth hormone and IGF-1 in healthy adults; epitalon's telomere effect is from lab cell studies only. Neither is shown to slow aging in people. No known interaction has been reported.

Sources (3)

No known interactionNo human studies found

Epitalon and GHK-Cu

Epitalon and GHK-Cu work differently; no studies tested them together. No human studies of these two together were found. Epitalon's telomere effect comes from lab cell studies; GHK-Cu supports collagen and skin repair in lab and animal work. They act through different mechanisms; no known interaction has been reported. Neither is shown to slow aging in people.

Sources (3)

No known interactionNo human studies found

Epitalon and NAD+

Epitalon and NAD+ have not been studied together; no known interaction reported. No human studies of these two together were found. Human trials mostly test oral NAD+ precursors such as nicotinamide riboside, which raised NAD+ levels and was well tolerated in healthy older adults. Injected NAD+ itself has much less trial data. Epitalon's telomere effect is from lab cell studies only.

Sources (3)

No known interactionNo human studies found

GHK-Cu and TB-500

GHK-Cu and TB-500 work differently; no studies tested them together. No human studies of these two together were found. GHK-Cu raises collagen and supports skin repair in lab and animal work. The FDA says it has no human exposure data for TB-500, a fragment of thymosin beta-4. No known interaction has been reported.

Sources (4)

No known interactionNo human studies found

Ipamorelin and HGH Fragment 176-191

No studies of this pair; no known interaction reported. No human studies of these two together were found. HGH Fragment 176-191 (sold as AOD-9604) has been studied for fat loss mainly in mice. There is no evidence that GH released by ipamorelin interferes with it. No known interaction reported.

Sources (2)

No known interactionNo human studies found

Kisspeptin and PT-141

No studies of kisspeptin with PT-141; kisspeptin is still experimental. No human studies of these two together were found. Kisspeptin activates the reproductive hormone axis and, in small one-day IV trials, changed sexual brain responses in men and women with low desire. PT-141 (Vyleesi) acts on melanocortin receptors and is approved for premenopausal women with low sexual desire.

Sources (3)

No known interactionNo human studies found

MOTS-c and 5-Amino-1MQ

No studies of MOTS-c with 5-Amino-1MQ; both are tested mainly in mice. No human studies of these two together were found. Both have been studied mostly in mice: MOTS-c improved insulin resistance, and 5-Amino-1MQ (an NNMT enzyme blocker) reduced weight and fat in obese mice. Human safety data for either are lacking.

Sources (3)

No known interactionNo human studies found

MOTS-c and Semaglutide

No studies of MOTS-c with semaglutide; no known interaction reported. No human studies of these two together were found. MOTS-c has been studied mainly in mice, where it improved insulin resistance and limited diet-related weight gain. The FDA says it has no human exposure data for MOTS-c.

Sources (2)

No known interactionNo human studies found

Semaglutide and AOD-9604

No studies of AOD-9604 with semaglutide; no known interaction reported. No human studies of these two together were found. In small human trials, AOD-9604 did not raise blood sugar or IGF-1. The FDA notes little safety data for AOD-9604 and serious adverse events that may be linked to it, though cause was unclear.

Sources (3)

No known interactionFDA label

Semaglutide and Birth control pills

In the label's study, semaglutide did not change birth control pill levels in a meaningful way. The Ozempic label reports a study with an ethinylestradiol/levonorgestrel birth control pill taken alongside semaglutide, measured at steady state, and states semaglutide did not affect the absorption of the tested pills to a clinically relevant degree. Unlike the tirzepatide labels, the semaglutide labels do not tell pill users to add a backup method.

Sources (1)

Novo Nordisk. OZEMPIC (semaglutide) injection, prescribing information, sections 7.2 and 12.3. FDA label (DailyMed), 2026

No known interactionNo human studies found

Semaglutide and HGH Fragment 176-191

No studies of HGH Fragment 176-191 with semaglutide. No human studies of these two together were found. HGH Fragment 176-191 is not an approved drug. The closest studied compound, AOD-9604 (a similar growth hormone end-fragment), did not raise blood sugar in mice or in small human trials, but that has not been shown for the fragment sold as 176-191.

Sources (2)

No known interactionNo human studies found

Semax and Selank

Semax and Selank have each been studied in people, but not together. No human studies of these two together were found. Selank was studied in Russia as an anti-anxiety drug, and Semax in Russian trials such as stroke recovery. A brain-scan study in healthy people tested each one separately against placebo, not the two combined. No known interaction has been reported.

Sources (3)

No known interactionNo human studies found

TB-500 and CJC-1295

No studies of TB-500 with CJC-1295 were found; no known interaction reported. No human studies of these two together were found. FDA says it has no human exposure data at all for TB-500, so there is nothing to say about how it combines with anything. No known interaction reported.

Sources (2)

No known interactionNo human studies found

TB-500 and HGH Fragment 176-191

No studies of TB-500 with HGH Fragment 176-191; neither has meaningful human data. No human studies of these two together were found. The FDA says it has found no human exposure data for TB-500. HGH Fragment 176-191 is closely related to AOD-9604, which was studied for fat loss mainly in animals. No known interaction has been reported.

Sources (2)

No known interactionNo human studies found

TB-500 and Ipamorelin

No studies of TB-500 with ipamorelin were found; no known interaction reported. No human studies of these two together were found. FDA says it has no human exposure data for TB-500. Ipamorelin has only small human studies. No known interaction reported.

Sources (2)

No known interactionNo human studies found

TB-500 and Retatrutide

No studies of TB-500 with retatrutide; both are unapproved. No human studies of these two together were found. TB-500 is not FDA-approved and has no human exposure data according to the FDA. Retatrutide is investigational and still in trials.

Sources (2)

No known interactionNo human studies found

TB-500 and Semaglutide

No studies of TB-500 with semaglutide; no known interaction reported. No human studies of these two together were found. TB-500 is not FDA-approved, and the FDA says it has no human exposure data for it, so its own safety is largely unknown.

Sources (1)

U.S. Food and Drug Administration. Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks. FDA web page, 2026

No known interactionNo human studies found

TB-500 and Tirzepatide

No studies of TB-500 with tirzepatide; no known interaction reported. No human studies of these two together were found. TB-500 is not FDA-approved, and the FDA says it has no human exposure data for it.

Sources (1)

U.S. Food and Drug Administration. Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks. FDA web page, 2026

No known interactionNo human studies found

Thymosin alpha-1 and KPV

Thymosin alpha-1 and KPV act on the immune system differently; no combination studies. No human studies of these two together were found. Thymosin alpha-1 has been tested in human trials such as chronic hepatitis B, with low-certainty results. KPV reduced colitis in mice through the NF-kB pathway and has no human data. No known interaction has been reported.

Sources (3)

Frequently asked questions

Is there a peptide interaction checker I can trust?+

Use any checker, including this one, as a starting point for a talk with your clinician, not as a green light. This one shows its sources for every pair: 71 reviewed pairs, 11 backed by FDA label text and 2 by human studies. The others are based on animal studies, on how each compound works, or on the fact that no study was found. Each card says which.

What does "no known interaction" mean?+

It means we searched PubMed, FDA labels and trial registries and found no reported interaction between the two. For most research peptides that is because nobody has studied the pair, not because it was tested and found safe. Treat it as "unknown", not "fine".

Can I take two GLP-1 medicines together, like semaglutide and tirzepatide?+

The FDA labels say no. The Wegovy label says using it with any other GLP-1 receptor agonist is not recommended, and the Zepbound label says the same for tirzepatide with any GLP-1 receptor agonist. Retatrutide is still investigational and also acts on the GLP-1 receptor.

Do GLP-1 medicines interact with birth control pills?+

The tirzepatide labels (Mounjaro, Zepbound) tell people on birth control pills to switch to a non-pill method or add a barrier method for 4 weeks after starting and after each dose increase, because tirzepatide slows stomach emptying. In the Ozempic label's study, semaglutide did not change pill levels in a meaningful way, and that label has no backup-method advice.

Why are so many pairs marked "no human studies"?+

Most research peptides, such as BPC-157, TB-500 and the growth hormone secretagogues, are not FDA approved and have little or no human research of any kind, let alone studies of combinations. We would rather say that plainly than guess.

Why is a pair I take missing?+

Either we have not reviewed it yet, or we could not find anything solid enough to publish. A missing pair shows as "no reviewed entry". It does not mean the pair is safe or unsafe. Ask your clinician or pharmacist.

Does Dose Track have an interaction checker in the app?+

Yes. The Dose Track app has an interaction checker next to your dose log, vial tracking, reminders and level charts. This free web version shows the reviewed, sourced pairs.

Peptide Interaction Checker

How each pair is rated

How we checked

All 71 reviewed pairs

Semaglutide and Retatrutide

Semaglutide and Tirzepatide

Tirzepatide and Retatrutide

CJC-1295 and GHRP-2

CJC-1295 and GHRP-6

CJC-1295 and Hexarelin

CJC-1295 and Ipamorelin

IGF-1 LR3 and CJC-1295

IGF-1 LR3 and Ipamorelin

Ipamorelin and Sermorelin

Melanotan II and PT-141

MK-677 and CJC-1295

MK-677 and Semaglutide

PT-141 and CJC-1295

PT-141 and Semaglutide

Retatrutide and CJC-1295

Semaglutide and Cagrilintide

Semaglutide and CJC-1295

Semaglutide and Insulin

Semaglutide and Oral medications (pills)

Semaglutide and Sulfonylureas

Sermorelin and GHRP-2

Sermorelin and GHRP-6

Sermorelin and Hexarelin

Tirzepatide and Birth control pills

Tirzepatide and CJC-1295

Tirzepatide and Insulin

Tirzepatide and Oral medications (pills)

Tirzepatide and Sulfonylureas

CJC-1295 and Sermorelin

GHRP-2 and GHRP-6

Hexarelin and Ipamorelin

HGH Fragment 176-191 and AOD-9604

Ipamorelin and GHRP-2

MK-677 and Ipamorelin

5-Amino-1MQ and Semaglutide

BPC-157 and CJC-1295

BPC-157 and GHK-Cu

BPC-157 and HGH Fragment 176-191

BPC-157 and Ipamorelin

BPC-157 and KPV

BPC-157 and PT-141

BPC-157 and Retatrutide

BPC-157 and Semaglutide

BPC-157 and Semax

BPC-157 and TB-500

BPC-157 and Thymosin alpha-1

BPC-157 and Tirzepatide

CJC-1295 and HGH Fragment 176-191

DSIP and CJC-1295

DSIP and Ipamorelin

Epitalon and BPC-157

Epitalon and CJC-1295

Epitalon and GHK-Cu

Epitalon and NAD+

GHK-Cu and TB-500

Ipamorelin and HGH Fragment 176-191

Kisspeptin and PT-141

MOTS-c and 5-Amino-1MQ

MOTS-c and Semaglutide

Semaglutide and AOD-9604

Semaglutide and Birth control pills

Semaglutide and HGH Fragment 176-191

Semax and Selank

TB-500 and CJC-1295

TB-500 and HGH Fragment 176-191

TB-500 and Ipamorelin

TB-500 and Retatrutide

TB-500 and Semaglutide

TB-500 and Tirzepatide

Thymosin alpha-1 and KPV

Frequently asked questions

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