A 2020 review links 5-HTP to digestive side effects, including nausea and vomiting, that rise with the dose. There is also a potentially serious interaction: 5-HTP raises serotonin, and the same review ties serotonin syndrome to antidepressant medications and to an excess of 5-HTP, so it should not be combined with antidepressants or other serotonin-affecting medication unless your healthcare provider approves. This guide covers what to expect, who should talk to a provider first, and how to take 5-HTP+ sensibly.
Key takeaways
- A 2020 review links 5-HTP to digestive side effects, including nausea and vomiting, that rise with the dose.
- 5-HTP raises serotonin, so it should not be combined with antidepressants or other serotonin-affecting medication unless your healthcare provider approves. A 2020 review links serotonin syndrome to antidepressant medications and to an excess of 5-HTP.
- 5-HTP+ is two capsules once a day, 20 to 30 minutes before a meal with an 8 oz. glass of water, which gives 200 mg of 5-HTP.
- The 5-HTP+ label says: "Do not exceed recommended dose. Pregnant or nursing mothers, children under the age of 18, and individuals with a known medical condition should consult a physician before using this or any dietary supplement."
- Do not take 5-HTP+ with Deep Calm+™, Restful Night+™ or Night Balance+™, which already contain 5-HTP.
What is 5-HTP, and why does it have side effects?
5-HTP (5-hydroxytryptophan) is a compound your body makes from the amino acid tryptophan, found in foods like turkey, eggs, dairy and seeds. Your body then converts 5-HTP into serotonin, a messenger involved in mood, and later into melatonin, your night-time signal. Supplements are usually extracted from the seeds of an African plant, Griffonia simplicifolia.
Because 5-HTP feeds directly into serotonin, its effects, wanted and unwanted, mostly come from that pathway. Serotonin is active in the gut as well as the brain, which helps explain why digestive effects are common.
Common 5-HTP side effects
A 2020 review in the International Journal of Molecular Sciences reports that 5-HTP may cause digestive problems that rise with the dose, and that nausea and vomiting have been reported at doses above 100 mg. A 5-HTP+ serving is 200 mg.
Keep to the labeled amount, since the review ties digestive problems to the dose, and take it as the label directs: with an 8 oz. glass of water, 20 to 30 minutes before a meal. If a side effect is bothersome or does not settle, stop and talk with your healthcare provider.
Serotonin interactions
Because 5-HTP raises serotonin, taking it with antidepressants or other serotonin-affecting medicines or supplements can lead to too much serotonin activity, a potentially serious state known as serotonin syndrome. The 2020 review notes that serotonin syndrome "results from antidepressant medications" and that "an excess of 5-HTP may be responsible for serotonin syndrome." Do not combine them unless your healthcare provider approves. Signs of serotonin syndrome can include agitation, a fast heartbeat, shivering, sweating and muscle twitching; seek medical help right away if they appear.
Talk with your healthcare provider before using 5-HTP if you take:
- SSRIs, SNRIs or other antidepressants
- Migraine medicines in the triptan family
- Certain pain medicines, cough medicines or sleep medicines
- Carbidopa, used with levodopa: the 2020 review reports that 5-HTP combined with a peripheral decarboxylase inhibitor such as carbidopa "may cause psychopathological side effects, like acute anxiety"
- Any supplement that also contains 5-HTP, L-tryptophan or St. John's Wort
If you have surgery scheduled, tell your surgeon you take 5-HTP and ask when to stop. If you are pregnant or nursing, avoid it unless your provider says otherwise. The 5-HTP+ label's caution reads: "Do not exceed recommended dose. Pregnant or nursing mothers, children under the age of 18, and individuals with a known medical condition should consult a physician before using this or any dietary supplement." It also says: "Keep out of reach of children. Do not use if safety seal is damaged or missing. Store in a cool, dry place."
A note on purity
Decades ago, a serious illness called eosinophilia-myalgia syndrome was linked to contaminated tryptophan products, and some 5-HTP products were later reported to contain a related impurity. Researchers still debate how much of that risk came from contamination rather than the compound itself. Either way, it is worth asking any brand what its testing covers.
Every batch of 5-HTP+ is third-party tested for purity and potency by an outside lab, and it is manufactured in USA with globally sourced materials in an NSF-certified, GMP-certified, FDA-registered facility. The Our Standards page explains what our batch testing covers and how to request the certificate of analysis for your bottle's batch.
Meet 5-HTP+: what is in it and how to take it
5-HTP+ is two capsules once a day, 20 to 30 minutes before a meal with an 8 oz. glass of water, which gives 200 mg of 5-HTP. Each serving also contains 328 mg of calcium as calcium carbonate. A 60-capsule bottle lasts 30 days. The label shows the actives by amount, with no proprietary blend.
| Label detail | 5-HTP+ |
|---|---|
| Serving size | 2 capsules |
| 5-HTP (Griffonia simplicifolia seed) | 200 mg per serving |
| Calcium (as carbonate) | 328 mg per serving |
| Capsule | Gelatin (not vegetarian) |
| Supply | 60 capsules, 30 days |
The label sets no required time of day: two capsules once a day, 20-30 minutes before a meal, so pick the meal that suits your day. If you are curious how it compares with melatonin, read 5-HTP vs. Melatonin: How They Differ and Which Fits Your Routine.
Do not take 5-HTP+ with Deep Calm+, Restful Night+ or Night Balance+, which already contain 5-HTP. Choose one approach. If you would like a mineral alongside it, Magnesium Glycinate+ is a common pairing. Follow each label: the Magnesium Glycinate+ label says three capsules once daily before a meal, and the 5-HTP+ label says two capsules once a day, 20-30 minutes before a meal with an 8 oz. glass of water.
Practical tips to keep 5-HTP comfortable
- Stick to the labeled amount. Do not double up to "make it work faster."
- Take it with a full glass of water before a meal, as directed.
- Give it time and consistent use before judging it.
- Keep a short note of how you feel, including any stomach effects.
- Check every other supplement you take for 5-HTP, tryptophan or St. John's Wort.
Frequently asked questions about 5-HTP side effects
Does 5-HTP make you tired?
Some people feel drowsy. See how it affects you before driving after a dose.
Can 5-HTP cause stomach problems?
Yes. Digestive problems, including nausea and vomiting, are reported with 5-HTP and rise with the dose. If stomach effects persist, stop and talk with your healthcare provider.
Can I take 5-HTP with antidepressants?
Not without your healthcare provider's approval. Combining 5-HTP with SSRIs, SNRIs or other serotonin-affecting medicines can cause too much serotonin activity, known as serotonin syndrome. A 2020 review in the International Journal of Molecular Sciences connects serotonin syndrome with antidepressant medicines and with too much 5-HTP.
Can I take 5-HTP every day?
The 5-HTP+ label direction is two capsules once a day. If you plan to use it for more than a few months, check in with your healthcare provider, especially if anything else in your routine changes.
Is 5-HTP+ vegetarian?
No. The capsule is made of gelatin: the label lists "Gelatin (capsule)" under Other Ingredients. It is gluten-free and non-GMO.
Related reading from our Wellness Hub
- 5-HTP: Meet 5-HTP+ for Healthy Mood Balance
- How to Increase Serotonin Naturally: Food, Light and Movement
- Our Real-Life Evening Wind-Down Routine for Better Sleep
Sources
- Maffei ME. 5-Hydroxytryptophan (5-HTP): Natural Occurrence, Analysis, Biosynthesis, Biotechnology, Physiology and Toxicology. Int J Mol Sci. 2020.
- Turner EH, Loftis JM, Blackwell AD. Serotonin a la carte: supplementation with the serotonin precursor 5-hydroxytryptophan. Pharmacology & Therapeutics, 2006.
- Young SN. How to increase serotonin in the human brain without drugs. J Psychiatry Neurosci, 2007
- NCCIH: St. John's Wort (updated May 2025)
Individual results vary.
These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
