Can You Take Sleep Supplements With Antidepressants?

It depends on the ingredient, and the person who answers for your own prescription is your pharmacist or GP. Tryptophan and 5-HTP act on serotonin, as SSRIs, SNRIs and MAOIs do, and are the ingredients to hold back without that conversation; ashwagandha, valerian, chamomile, lemon balm and theanine mainly add drowsiness, which matters most with a sedating antidepressant such as mirtazapine or amitriptyline; magnesium has no documented interaction with any antidepressant; and melatonin is a prescription-only medicine in the UK. No sleep supplement has been assessed alongside an antidepressant in the way medicines are assessed against each other, and every NHS page for these medicines carries the same instruction, in the citalopram wording: "tell your doctor if you're taking any other medicines, herbal remedies, vitamins or supplements".¹ The record for each ingredient follows, in the NHS wording for seven antidepressants, under the Wellgard sleep guide.

Why is this question so hard to get answered?

Because the two halves are regulated apart. A medicine's interactions are studied before it is licensed; a food supplement's are not. The NHS pages for all seven antidepressants name one supplement to avoid, St John's wort, and otherwise hand the question to the prescriber.^{1, 2, 3, 4, 5, 6, 7} Of herbal remedies the NHS says: "They're not tested in the same way as pharmacy and prescription medicines" and "They're generally not tested for the effect they have on other medicines".⁷

Which sleep-supplement ingredients act on serotonin?

Tryptophan and 5-HTP, directly; ashwagandha, measurably but by a different route. The NHS says citalopram is "thought to work by increasing the level of serotonin", and describes serotonin syndrome as "a rare but serious condition that causes a fast heartbeat, sweating, shaking, twitching muscles and feeling confused or agitated".⁸ A 2023 review: it arises "through therapeutic use or overdose of a single serotonergic drug or as a drug interaction between two or more serotonergic drugs".⁹

Tryptophan is the amino acid the body converts into serotonin. Five case reports describe a toxic reaction after fluoxetine was combined with L-tryptophan, and a review of tryptophan alongside antidepressants concluded that "the risk of the serotonin syndrome is small, but it can occur".^{10, 11} The one controlled trial to pair them, under hospital supervision in 30 people with depression at prescription-level doses of tryptophan, recorded no serotonin syndrome and daytime drowsiness at the higher dose.¹² In the UK, L-tryptophan may be added to a food supplement only if "the recommended daily dose for that food supplement does not exceed 220 mg", and the pooled sleep effect, less time awake after falling asleep, appeared at 1 g or more a day.^{13, 14} A GB supplement therefore holds 220 mg at most. Does tryptophan help you sleep? has the foods and the limit.

5-HTP is one step further along the same pathway and is not capped by the regulations. A review of 5-HTP as a supplement covers its "safety issues ... with emphasis on eosinophilia myalgia syndrome (EMS) and serotonin syndrome".¹⁵ It belongs in the same conversation as tryptophan.

Ashwagandha raised circulating serotonin by a mean of 31.75 ng/mL across 23 placebo-controlled trials in 1,706 adults, with heterogeneity flagged by the authors.¹⁶ No trial has given it with an antidepressant, so this is a reason to involve the prescriber, not a documented interaction. Who should not take ashwagandha? covers the liver and thyroid cautions beside it.

Which ingredients add drowsiness to a sedating antidepressant?

Most of the herbal ones, in theory, and it matters most for mirtazapine and amitriptyline. The NHS lists "feeling drowsy or sleepy" among mirtazapine's common side effects and names benzodiazepines among the medicines that "may not mix well" with it.⁶ For amitriptyline: "Taking amitriptyline with opioid medicines can increase your risk of becoming very drowsy and having breathing problems", and "There's not enough information to say that other complementary medicines and herbal remedies are safe to take with amitriptyline".⁷

Valerian is the clearest case: the NHS insomnia page says pharmacy sleep aids containing "valerian or lavender" "may help you sleep better for 1 to 2 weeks", "should not be taken for any longer", and "Check with your doctor before taking anything for your sleep problems."¹⁷ Chamomile and lemon balm have no interaction study with any antidepressant; the caution is additive drowsiness, untested either way. Ashwagandha: across 23 trials of root extract in 2,317 healthy adults, "transient drowsiness" was among the mild events, infrequent and reported in both groups.¹⁸ Theanine has no interaction study; the label caution for anyone on sedatives or antidepressants is to ask a pharmacist or GP first, which is where what L-theanine does leaves it too.

Is magnesium a problem with antidepressants?

Not on anything published. Nothing published reports serotonin syndrome or any other interaction between a magnesium supplement and an antidepressant; the one record pairing the words concerns a magnesium salt of an epilepsy medicine taken with venlafaxine, a medicine interaction rather than a supplement one.¹⁹ Magnesium does not act on serotonin reuptake and none of the seven NHS pages names it. Its documented interactions are with tetracycline and quinolone antibiotics and bisphosphonates, whose absorption it blocks unless doses are hours apart; what not to take with magnesium gives the spacing.

Do antidepressants themselves change sleep?

Yes, in both directions, and often this is the real question. "Problems sleeping" is a listed common side effect of citalopram and sertraline, with "dizziness or drowsiness" alongside on the sertraline page; mirtazapine sits at the other end.^{6, 8, 20} The NHS insomnia page notes that "Many medicines can also cause insomnia".¹⁷ None of this is a reason to change or stop an antidepressant on your own; it is a reason to tell the prescriber that sleep is the problem. When to see a GP about sleep lists the signs that should not wait.

What should you ask before trying anything?

Three questions, with the ingredient list in your hand. First: "I take [medicine]; does anything on this label act on serotonin?" (tryptophan, 5-HTP, St John's wort, ashwagandha). Second: "Does anything here add to drowsiness with my medicine?" (valerian, chamomile, lemon balm, ashwagandha, theanine). Third: "If I notice anything, what do I stop first and who do I call?" The NHS rule is "Always check with your doctor or a pharmacist before starting any new medicine while you're taking amitriptyline".⁷ If serotonin syndrome symptoms appear, call 111 if you "think you might be having serious side effects",⁸ and 999 for a swollen throat or tongue or difficulty breathing.^{8, 20} Suspected side effects of a medicine go to the Yellow Card scheme ("Anyone can report a problem").²¹ Can you take collagen with antidepressants? applies the same framework to a protein.

Frequently asked questions

Can I take 5-HTP with sertraline?

Not without your pharmacist or prescriber agreeing. Both act on serotonin, the NHS lists serotonin syndrome among sertraline's serious side effects, and the 5-HTP review singles out serotonin syndrome.^{15, 20}

Can you take tryptophan with antidepressants?

Only with your pharmacist or prescriber agreeing: five case reports describe a toxic reaction with fluoxetine, and a review puts the serotonin syndrome risk as small but real.^{10, 11} A GB supplement holds 220 mg at most.¹³

Can I take magnesium glycinate with paroxetine or sertraline?

No interaction between any magnesium supplement and any antidepressant has been documented, and magnesium does not act on serotonin.¹⁹ Tell your pharmacist, as the NHS asks for every supplement.¹

Is there a sleep aid I can take with sertraline?

No supplement has been assessed for that, so ask the pharmacist, who can see your full list; the NHS's own answer for pharmacy sleep aids is 1 to 2 weeks at most and "Check with your doctor before taking anything for your sleep problems".¹⁷

Sources

1. NHS. Taking citalopram with other medicines and herbal supplements. nhs.uk.
2. NHS. Taking sertraline with other medicines and herbal supplements. nhs.uk.
3. NHS. Taking fluoxetine with other medicines and herbal supplements. nhs.uk.
4. NHS. Taking escitalopram with other medicines and herbal supplements. nhs.uk.
5. NHS. Taking venlafaxine with other medicines and herbal supplements. nhs.uk.
6. NHS. Mirtazapine: other medicines and herbal supplements; side effects. nhs.uk.
7. NHS. Taking amitriptyline for depression with other medicines and herbal supplements. nhs.uk.
8. NHS. Citalopram: about citalopram; side effects. nhs.uk.
9. Mikkelsen N, Damkier P, Pedersen SA. Serotonin syndrome: a focused review. Basic & Clinical Pharmacology & Toxicology, 2023. PubMed 37309284.
10. Steiner W, Fontaine R. Toxic reaction following the combined administration of fluoxetine and L-tryptophan: five case reports. Biological Psychiatry, 1986. PubMed 3488767.
11. Young SN. Use of tryptophan in combination with other antidepressant treatments: a review. Journal of Psychiatry and Neuroscience, 1991. PubMed 1797098.
12. Levitan RD, et al. Randomized placebo-controlled trial of tryptophan combined with fluoxetine in major depressive disorder. Journal of Psychiatry and Neuroscience, 2000. PubMed 11022398.
13. The Tryptophan in Food (England) Regulations 2005, SI 2005/2630, regulation 5. legislation.gov.uk.
14. Sutanto CN, Loh WW, Kim JE. The impact of tryptophan supplementation on sleep quality: a systematic review and meta-analysis. Nutrition Reviews, 2022. PubMed 33942088.
15. Turner EH, Loftis JM, Blackwell AD. Serotonin a la carte: supplementation with the serotonin precursor 5-hydroxytryptophan. Pharmacology & Therapeutics, 2006. PubMed 16023217.
16. Fornalik M, et al. Hormonal modulation with Withania somnifera: systematic review and meta-analysis of randomized-controlled trials. Planta Medica, 2026. PubMed 41740946.
17. NHS. Insomnia. nhs.uk.
18. Coope OC, et al. Safety and tolerability of standardised ashwagandha root extract in healthy adults: a systematic review of biomarkers and adverse events. Pharmaceuticals, 2026. PubMed 42198398.
19. Zhan Z, Cao CS, Huang L. Serotonin syndrome induced by a single dose of venlafaxine and magnesium valproate. Psychiatria Danubina, 2021. PubMed 34185746.
20. NHS. Side effects of sertraline. nhs.uk.
21. GOV.UK. Report a problem with a medicine or medical device (Yellow Card scheme). gov.uk.
22. NHS. Taking melatonin with other medicines and herbal supplements. nhs.uk.
23. NHS. About melatonin. nhs.uk.

General information, not medical advice. Show your pharmacist or GP the full ingredient list before starting any sleep supplement, and never stop or change your medicine without speaking to them first.