Signs of high serotonin and the top 5 supplements to lower it

Serotonin is synthesized in both the brain as well as in the gut, but for this article, I’m just going to focus on the serotonin in the brain as it influences how you feel mentally and determines certain behaviors. Whereas gut serotonin doesn’t have the same effect because it cannot cross the blood-brain barrier, meaning it stays within the gut where it is formed due to foods that irritate the gut. Serotonin is synthesized from the amino acid tryptophan via the enzyme tryptophan hydroxylase (TPH).

Once released from neurons, serotonin binds to its receptors, 5-HT1 to 5-HT7, each having a different effect. Serotonin transporters (SERT) remove serotonin from the synaptic cleft, terminating its action. Serotonin is then broken down by monoamine oxidase A (MAO-A) and COMT.

So we want to inhibit TPH, block serotonin receptors, increase SERT and MAO-A in order to reduce the effects of serotonin.

Here are a few signs of elevated serotonin:

  • rigid behavior and thinking (r), obedient (zombie behavior) (A)
  • behavioral inhibition, depersonalization and harm avoidance (A)
  • procrastination, no motivation or focus, brain fog, etc. (A)
  • lack of perspective or awareness, distorted perception when reading or listening to someone talk (r)
  • reduced creativity (r), anti-novelty (r)
  • social isolation/anxiety and general anxiety (A)
  • emotionally blunt, apathy, can’t connect emotionally with people (r)
  • OCD (via 5-HT1B and 5-HT2C activation)
  • insomnia (via overstimulation of 5-HT1A/1B and 5-HT2A)
  • lack of appetite (r)
  • fatigue, chills, agitation, aggression (A)
  • fearful behavior, learned helplessness, shock/freeze (serotonin protects the organism when it perceives that the stressor is too big to overcome and causes shutdown) (A)
  • reduced sensory responsiveness such as smell, sounds, taste (not exclusive to high serotonin) (1)
  • flushing (r), sweating (r), diarrhea (serotonin stimulates small intestine smooth muscle, but inhibits the large) (r), nausea (5-HT3) (r), reduced urination (r), muscle and joint pains (r), tinnitus (r), vertigo (r).
  • Sensitivity to light, sound, visual disturbances, easily frightened, jumpy (coupled with adrenaline) and head twitching (5-HT1A agonists reduce head twitching, due to negative feedback signaling for serotonin production) (2)
  • Reduced NMDA activity (r)

The effects of elevated serotonin on hormones & neurotransmitters

  • Increases aldosterone (aldosterone increases estrogen and high blood pressure and can make you look bloated/water retention) (r)
  • Increases prolactin release (mainly through 5-HT2A) (3),
  • Elevates glucocorticoids & ACTH (mainly through 5-HT2C)
  • Is correlated with estrogen receptors (through 5-HT4) (4)
  • Inhibits testosterone synthesis (r)
  • Inhibits dopamine release in frontal cortex (through 5-HT1B)

Inhibit TPH


DHT inhibits tryptophan hydroxylase 1 (TPH1). (72) More on boosting DHT here. A super potent way to boost DHT and to lower estrogen is via androsterone. Start with 1 drop (1mg) daily and work up to 5 drops (5mg) if needed.

  • Androsterone – 1mg per drop, 240 drops (apply only topically)

Inhibit serotonin receptors


Yohimbine inhibits several serotonin receptors, but might be too stimulating for certain people, so it might have to be taken with magnolia.

  • Yohimbine – 3mg yohimbine HCL per serving, 60 servings
  • Magnolia – 400mg per cap, 60 caps


Lysine prevents serotonin (5-HT)-induced anxiety, diarrhea, ileum contractions, and tachycardia and in stress-induced fecal excretion. (5) More on lysine here

  • Lysine – 500mg per cap, 250 caps. Start with 500mg with every meal.

Increase SERT


Forskolin increases SERT, dopamine and it’s receptors, free testosterone and vasodilation. All in all, this is a pretty good herb.

  • Forskolin – 400mg (40mg forskolin extract) per cap, 60 caps

Increase MAO-A

Vitamin B2

Riboflavin is a cofactor of the enzyme MAO-A, which increases catecholamine degradation such as, serotonin and noradrenaline, thus keeping catecholamine levels in balance. MAO-A predominantly breaks down serotonin, and is great for increasing the dopamine:serotonin ratio. More on vitamin B2 here

  • Vitamin B2 – 100mg riboflavin HCL per cap, 100 caps

Want more awesome content like this?

Success! You're on the list.

7 thoughts on “Signs of high serotonin and the top 5 supplements to lower it”

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.

%d bloggers like this: