Hot water and Humalog

Hello everyone just a quick question,

When I was diagnosed in 2005, the hospital I went to had someone like a Diabetes Therapist. She helped me deal with having Diabetes and taught me how to inject myself and whatnot but she was not a doctor or a nurse. I remember her telling me not to shower right after I take my Humalog insulin because the hot water would make the insulin rush in and cause a low, Humalog is rapid acting anyways right? Every doctor I have seen since then has said they have not heard of that. Does anyone know anything about this? Has anyone ever done this and had no different results?



Our daughter was diagnosed this past December and we were told the same thing.   In fact, one of the first days we had her home from the hospital, we gave her a bath (this was more than 30 minutes after her Humalog injection) and she had a low.  Of course, this could be unrelated, but the nurses did tell us not to bathe within 30 minutes of Humalog for this reason.   By the way, she is 8.

I was told the same thing. Or maybe I read it in a book. Anyway, for over two years it was a pain in the butt to schedule his insulin dose around bath time. Back in December I was told by one of his nurses, who has diabetes, that it was not true. I've since stopped waiting the 30 minutes and haven't noticed any reaction.

ive never heard of that- i always shower after i bolus/correct- no problems yet

We were told the same thing and read it in a book given to us at the hospital.

We were told the same thing, and have experienced it because I forgot!

2 different times I bathed Benjamin right after his Humalog injection & both times his blood sugar dropped very quickly.  I guess it could be a random thing, but as soon as I stopped he didn't go low at that time & I didn't make any other changes.



We were told not to take a bath, but I thought it was that it could cause a high after (like the insulin could seep out of the injection site.) We were told a shower was OK. Somewhere on here I know I read that people have noticed that a hot bath will just make their kids BGs drop (unrelated to insulin injection). Some have suggested it as a way to help with highs during illness or for other unexplained reasons.

I'm not sure if this has anything to do with insulin or not, but I know I have seen on signs at hot tubs that it is not recommended for diabetes to consult with your doctor first. so I guess it could say that because it effects our blood sugar?

WOW! Ive never heard this but it all make sense now. My boyfriend and I were wondering why I go low after a hot shower or even in a hot tub. This has definitely happened to me a few times.

I never knew this -- I'll have to pay attention if a hot shower after humalog makes me low.

But, I did learn that if you're on MDI and high, to rub the injection site -- it will speed the absorption of the insulin. I thought it was the rubbing, but maybe it's the heat?

what is MDI?

MDI means Mutiple Daily Injections

Sweet Blood

It hasn't happened to me but I have heard of it. It has something to do with heat making your blood vessels increase in size

Hi Kevin

I was just talking to my Endo the other day about this exact question.  When you're talking about 'hot water', think in terms of a hot tub, where the water is probably getting up into the 130's (degrees).  When your body heats up, it starts to sweat and also it starts to metabolize faster.  So, you'll see on heat blankets and hot tubs a warning to not use it if you're diabetic b/c you might heat up too much.

Your shower water is most likely not above 130 degrees so unless you are sweating in the shower (in which case you'd be really unconfortable), you're fine and the Humalog will process normally.

Hope that helps!


~Blake's Mom

I never knew that about hot tubs. I've never had a problem w/ them, but maybe it was long after injecting. Maybe more difficult on a pump?

I usually drop significantly after showering and find I'm often low.  I don't use Humalog though - I use Novolog through the pump and I think I drop even if I haven't bolused right before showering. 

Increased temperature (~110-120') causes vasodilation of the blood vessels in the adipose (fatty) tissue. Normally, what happens is, you inject the Humalog insulin, and your body, over time, bioactivates it and it enters the blood stream at a constant rate. When you increase temperature, like you do when you take a hot bath, it causes an increase in blood supply to the area where you have injected the insulin, which increases the bioactivation and uptake. So, instead of a standard rate of absorption, you get a spike.

I have even seen situations where 3-4 hours after injecting I'll get a dip when taking a hot bath. This is because, despite a fairly even distribution of blood vessels in fatty tissue, insulin will still "pool" at injection sites, which causes a sort of buffering effect. When you take a warm bath, the fat cells and blood vessel expansion makes those pools (which are quite small, by the by) finally be absorbed by the body.

Just make sure, if you're ever hottubbin' or relaxing in a hot bath, to do so with a good BG of about 120 or so - which should generally protect you from lows. Or at least it's worked for me.

I have seen less of this since I went on the pump.... for whatever reason.

Is that rule for humalog in particular or most fast acting insulins?  (I ask since most people who said they heard it or experienced it mentioned humalog also)

[quote user="MJ"]

 When you increase temperature, like you do when you take a hot bath, it causes an increase in blood supply to the area where you have injected the insulin, which increases the bioactivation and uptake. So, instead of a standard rate of absorption, you get a spike.



Great explanation!  This is so cool...I was never told anything about heat causing lows, but I do sometimes drop a little while I'm in the shower.  Most of the time I think it's counteracted by the fact that I have my pump disconnected the whole time though, so I'm not getting any basal insulin.


saw this happen right away,asked a nurse who didn't know the answer...I looked and found the answer from one of our first  books we got  on d--Understanding's the one with the pink panther on the front cover,anyway, here is what it says---Question..We were recently told at a clinic visit that our child shoul not be given insulin just prior to a hot bath,shower or hot tub.Would you please explain the reason for this ?  Answer--The hot bath or shower (or hot tub ) increases the blood flow to the skin.As more blood flows to this area,more insulin is rapidly taken up by the blood ( probably primarily ) Humalog.Novolog,or Regular insulins ).This can then result in severe low blood sugar. The answer is to ALWAYS TAKE THE INSULIN AFTER THE HOT SHOWER OR BATH . The  bath or shower should  not be taken in the 30-90 minutes after Humalog/NovoLog or in the four hours after taking Regular insulin. This may help to prevent a severe low blood of the newer books may say something different-but we sure saw this happen more than once,hate lows !