Short answer. 5-HTP (5-hydroxytryptophan) is the molecule your body makes from the amino acid tryptophan on the way to serotonin, supplied in supplements from Griffonia simplicifolia seed. A Cochrane review rated only 2 of 108 trials solid enough to count, so the mood evidence is thin. No RDA or upper limit exists, and it should never be taken with antidepressants.
What is 5-HTP, and how does it become serotonin?
5-HTP is the halfway molecule between the amino acid tryptophan and serotonin. The body builds serotonin in two steps: one enzyme turns tryptophan into 5-HTP, and a second enzyme, using vitamin B6 in its active form (P-5-P), turns 5-HTP into serotonin. At night the body carries some of that serotonin two steps further to melatonin, the signal for sleep timing.
Most tryptophan never takes this route. Only about 3% of the tryptophan you eat is used to make serotonin anywhere in the body, while roughly 90% of tryptophan breakdown runs down a separate path called the kynurenine pathway (Richard 2009, PMID 20651948). Taking 5-HTP skips the first and slowest step, so it gives the body raw material that is already one stage closer to serotonin (Birdsall 1998, PMID 9727088).
Is 5-HTP a serotonin supplement, and does it reach the brain?
It is a serotonin precursor, not serotonin itself, and the honest answer to whether it reaches the brain is: partly. 5-HTP is well absorbed by mouth, with about 70% reaching the bloodstream, and it does not need a transporter, so other amino acids and meals do not block it; 5-HTP itself can cross into the brain (Birdsall 1998, PMID 9727088). The catch is that much of an oral dose is converted to serotonin out in the body before it gets there, and how much reaches the brain depends on how much of that peripheral conversion happens first (Turner 2006, PMID 16023217). Serotonin made outside the brain cannot cross in at all, and more than 90% of the body's serotonin is made in the gut, not the brain (Yano 2015, PMID 25860609). So the useful goal is supply, giving the body enough raw material, rather than chasing "more serotonin."
Where does the 5-HTP in supplements come from?
From a plant. Supplement 5-HTP is extracted from the seeds of Griffonia simplicifolia, a West African shrub whose seeds are naturally rich in it. Two ASDHelp products name that source on the label: SeroTonic+ Spray and Brain Soothing Liquid both list 5-HTP from Griffonia simplicifolia seed. Unlike tryptophan, 5-HTP cannot be pulled away into making niacin or protein, so once it is absorbed it has one main job (Birdsall 1998, PMID 9727088).
What do studies show about 5-HTP and mood?
Less than the marketing suggests. The most careful look is a Cochrane review that located 108 trials of 5-HTP and tryptophan for low mood, then found only 2 of them, with 64 patients in total, were well enough designed to trust; the reviewers called the evidence too weak to be conclusive (Shaw 2002, PMID 11869656). A later systematic review pulled together 13 studies, pooled 7 of them, and reached the same kind of verdict: most of the research is weak, few trials used a placebo group, and better studies are needed before anyone can say how well 5-HTP works for people with a diagnosed mood disorder (Javelle 2020, PMID 31504850). In plain terms, 5-HTP is widely sold for low mood, but the trials behind it are small and mixed. It is a supplement, not a stand-in for professional care.
How much 5-HTP is in supplements, and which ASDHelp products contain it?
There is no official amount for 5-HTP. It is not a vitamin or mineral, so there is no Recommended Dietary Allowance and no Tolerable Upper Intake Level, and labels state that a Daily Value has not been established. Studies have used a wide range of doses, which is one reason their results are hard to compare (Javelle 2020, PMID 31504850). So the safest approach is to follow the label on one product and talk to a clinician about the amount.
Five ASDHelp products contain 5-HTP. The rule that matters most: take only one of them at a time, ever.
| Product | 5-HTP per label serving | What else is in it |
|---|---|---|
| Brain Calm | 50 mg (2 capsules) | GABA and L-theanine for daytime calm; vitamin B6 2.5 mg |
| SeroTonic+ Spray | 16 mg (2 sprays); up to 48 mg a day at the label's three servings | L-tryptophan 16 mg and active B6 2 mg; label carries an antidepressant caution |
| Sleep Formula | 100 mg (2 capsules) | Melatonin and calming herbs for bedtime; B6 10 mg |
| Sleep Lozenges | 100 mg (2 tablets) | Melatonin and L-theanine in a chewable; B6 10 mg |
| Brain Soothing Liquid | Not disclosed, inside an 830 mg blend | Also contains lithium orotate, so it's for adults only and never taken with another lithium product |
None of these labels gives a children's dose. Brain Calm, Sleep Formula and Sleep Lozenges list an adult serving only; SeroTonic+ Spray and Brain Soothing Liquid ask you to check with a healthcare professional before any use by a minor. So 5-HTP is not for a child unless their clinician directs it. We also keep every active to one product at a time, which is why you never pair two 5-HTP products; the reasoning is in one of each.
Two more products sit near 5-HTP without carrying it. Vitamin B6 P-5-P supplies 30 mg of the active B6 that the body uses to turn 5-HTP into serotonin, and it holds no 5-HTP. Spectrum Neurotransmitter Support lists 80 mg of tryptophan, the step before 5-HTP, and no 5-HTP at all. Count your B6 across everything you take: ASDHelp keeps total added B6 at or under 25 mg a day for adults and 10 mg for children unless a clinician sets a different amount, because high-dose B6 can harm sensory nerves. Vitamin B6 P-5-P at 30 mg is already over the adult ceiling on its own, so it is for when B6 is the only gap, not an add-on. Our vitamin B6 page lists the limits by age.
What are the side effects of 5-HTP?
The older trials didn't turn up many. A 1987 review of the 5-HTP studies up to that point found relatively few adverse effects in the people given it (Byerley 1987, PMID 3298325). That review is old and the trials behind it were small, so the two safety questions that matter more today are product purity and the other medicines you take.
There is also a safety story worth knowing. Years ago, a contaminated batch of a related supplement, L-tryptophan, was linked to an outbreak of eosinophilia-myalgia syndrome, a serious illness with severe muscle pain and a high white-cell count. A family later became ill after taking 5-HTP that carried an impurity; when they switched to 5-HTP without it, the blood abnormality resolved (Michelson 1994, PMID 7699627). Chemists went on to find a similar contaminant, nicknamed "Peak X," in commercial 5-HTP sold over the counter, and identified it as a probable nerve toxin (Klarskov 2003, PMID 12508395). This is not a reason to panic, because no modern outbreak has been tied to 5-HTP, but it is a strong reason to buy from a maker that tests each batch for purity rather than the cheapest bottle on the shelf.
Can you take 5-HTP with antidepressants?
No. This is the firm rule. 5-HTP pushes the body to make more serotonin, and antidepressants raise serotonin too, so taking them together can drive serotonin too high and cause serotonin syndrome, which can be dangerous. The same caution applies to some migraine and pain medicines, to other supplements or herbs that act on serotonin, and, for added drowsiness, to sedatives. Signs of serotonin syndrome include agitation or confusion, a fast heartbeat, sweating, shivering, tremor and twitching muscles (Mikkelsen 2023, PMID 37309284). SeroTonic+ Spray already prints an antidepressant caution on its label, and the same logic covers every 5-HTP product here.
So if you take any medicine for mood, ask your prescriber before adding 5-HTP, and do not start it on your own. If you are in crisis or thinking about harming yourself, call or text 988 in the US, the Suicide and Crisis Lifeline, now, or your local emergency number.
What is the difference between 5-HTP and L-tryptophan?
They sit one step apart on the same path. Tryptophan is the essential amino acid you get from food; the body turns a small part of it into 5-HTP, and 5-HTP into serotonin. The appeal of 5-HTP is that it skips the slow first step and cannot be pulled away into making niacin or protein the way tryptophan can (Birdsall 1998, PMID 9727088). Tryptophan, for its part, has to compete with several other amino acids for the same doorway into the brain, which limits how much gets through (Richard 2009, PMID 20651948). SeroTonic+ Spray actually carries both, 16 mg of each per serving. For a closer look at the amino acid, see our L-tryptophan page, and for the food and lifestyle side of raising serotonin, read how amino acids become the brain's messengers.
Questions to take to your doctor
- I take a medicine for mood, migraine or pain, or another serotonin-acting supplement. Is any 5-HTP product safe for me, or off the table?
- If 5-HTP is reasonable, which single product and what amount, and how will we know within a few weeks whether to keep it?
- How much vitamin B6 am I getting across all my supplements, and is the total under the limit for my age?
- Is this for an adult only, or has a clinician set a specific amount for a child?
For where 5-HTP fits a wider plan, see our Calm Support and Rest protocols, each built around one product per job.
Sources
- Shaw K, Turner J, Del Mar C. Tryptophan and 5-hydroxytryptophan for depression. Cochrane Database Syst Rev 2002. PMID 11869656
- Javelle F et al. Effects of 5-hydroxytryptophan on distinct types of depression: a systematic review and meta-analysis. Nutr Rev 2020. PMID 31504850
- Birdsall TC. 5-Hydroxytryptophan: a clinically-effective serotonin precursor. Altern Med Rev 1998. PMID 9727088
- Turner EH, Loftis JM, Blackwell AD. Serotonin a la carte: supplementation with the serotonin precursor 5-hydroxytryptophan. Pharmacol Ther 2006. PMID 16023217
- Richard DM et al. L-Tryptophan: basic metabolic functions, behavioral research and therapeutic indications. Int J Tryptophan Res 2009. PMID 20651948
- Yano JM et al. Indigenous bacteria from the gut microbiota regulate host serotonin biosynthesis. Cell 2015. PMID 25860609
- Mikkelsen N, Damkier P, Pedersen SA. Serotonin syndrome, a focused review. Basic Clin Pharmacol Toxicol 2023. PMID 37309284
- Byerley WF, Judd LL, Reimherr FW, Grosser BI. 5-Hydroxytryptophan: a review of its antidepressant efficacy and adverse effects. J Clin Psychopharmacol 1987. PMID 3298325
- Michelson D et al. An eosinophilia-myalgia syndrome related disorder associated with exposure to L-5-hydroxytryptophan. J Rheumatol 1994. PMID 7699627
- Klarskov K et al. Structural characterization of a case-implicated contaminant, "Peak X," in commercial preparations of 5-hydroxytryptophan. J Rheumatol 2003. PMID 12508395
- StatPearls. Serotonin Syndrome (NCBI Bookshelf). ncbi.nlm.nih.gov/books/NBK482377
These statements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure or prevent any disease. This article is educational and is not medical advice.