If the maximum units of Botox one can get every 3 months is 400 units, can I still get more if the Botox is not working?

Hello! My name is Jessica, I am a physician assistant, and one of the providers at Aesthetic Skin - Winnetka & Chicago. This is a great question. The commonly referenced maximum of 400 units of Botox every three months is a general guideline intended to ensure safety and minimize the risk of side effects, but it’s not an absolute, one-size-fits-all rule. If you’re still experiencing sweating after receiving 100 units per underarm (200 units total for both) plus 100 units in each trapezius (another 200 units), totaling 400 units, some providers may consider adding a small additional dose to improve effectiveness, especially if the sweating hasn’t fully responded. However, this decision depends heavily on your individual health and treatment history. Exceeding the 400-unit guideline should be approached cautiously, with close medical supervision, because higher doses can increase the risk of side effects like muscle weakness or systemic effects. I hope this helps and best of luck!

Injecting additional 25 units on each side should be safe. It also depends on the weight of the individual patient. Heavier patients may be able to tolerate higher doses.

100 units per underarm is a high dose for sweating. I do a lot of these treatments and rarely need to use that much. There could be several factors at play including injection technique, dilution, and quality of product. In those with severe sweating, I will usually combine with radiofrequency treatments with success. Make sure you are under the care of an experienced physician.

Thank you for your question.

The 400-unit limit every 3 months for Botox (onabotulinumtoxinA) is generally considered a guideline based on safety data from clinical trials and FDA approval. It’s not necessarily a strict, unbreakable rule — but rather a recommended maximum total dose to minimize the risk of side effects, such as antibody formation (which can lead to treatment resistance), systemic spread, or muscle weakness in distant areas.

In your case:
You’ve received:
200 units for the underarms (100 units each side)
200 units for the trapezius muscles
That totals 400 units — a high, but still within the typical safe range for therapeutic use.

If you’re still experiencing underarm sweating 3 weeks after injection, it may be due to:
Inadequate dose (some patients require a bit more than average)
Less-than-ideal injection technique or placement
Primary resistance (rare) or secondary resistance due to antibodies (less common but possible in high cumulative doses over time)
Other factors such as thyroid issues or medications that increase sweating

Regarding adding more:
It is sometimes clinically appropriate to administer a small touch-up dose if there’s been an inadequate response, particularly in focal areas like the underarms. A modest increase, such as 25 units per axilla, may be reasonable if you’re still symptomatic — but only under close supervision by your treating provider.

The 400-unit guideline is not absolutely set in stone, but exceeding it regularly may increase risks.

You should consult with your injector to evaluate why the initial treatment wasn’t fully effective.

A small supplemental dose might be considered safe if clinically indicated, but this should be individualized based on your health history and prior response to Botox.

I recommend a follow-up visit with your provider to assess your results and discuss whether a touch-up is appropriate.

Thank you for your question. 400 units every 3 months is a general guideline. If you are still experiencing hyperhidrosis with that much, you may wish to explore other options. RF microneedling does a very competent job with halting hyperhidrosis and may require 2-3 treatments within 3 months, and follow up treatment annually. A consultation with a board-certified plastic surgeon can present these choices for you. Good luck on your journey!

If you have received a high dose of Botox and are still having issues you may not have improvement with more units. You may want to explore other options with your surgeon to help with your hyperhydrosis symptoms.

If you haven't experienced relief from the Botox you've already received, you have to start asking yourself if an additional treatment with a small amount will make a difference. At this point, I recommend pursuing a discussion for other potentially more effective treatments for hyperhidrosis.