I too am 2 weeks late and didnt think it could be the Alli because it works in the digestive tract, but after reading these posts I am changing my mind. I will contact my Dr, but have ruled out that it is probably the Alli.

Wow!!!! It's good to know that I'm not the only one who's period is being affected by Alli. I am almost three weeks late! For the first couple of weeks Alli was working great. I felt good and I was loosing weight.....but in the last two weeks I might have gained it back because of my PMS cravings. I usually get them for a day or two but not two weeks!!!! Complete sabotage! I now feel even worst about myself then i did to begin with. Some answers PlEASE!!! Thank you.

Hi bce666,

Studies show that orlistat does not interfere with hormonal contraceptives or your menstrual period.  But it is recommended to speak to your personal healthcare professional if you have any questions.  Each person's body reacts differently to a change in regimen be it diet, exercise or medication.

Estrogen is stored in the fat tissue, your body may be reacting to a change in distribution, but only your physician can fully if this is the case.

Hope this helps.

Sophia De Monte RPh

I am just wondering...I think that the menstral cycle is an inconvenience.  I surely do not mind not having an menstrual.  I know that I am not pregnant... Is there any other harm that I'm not seeing from missing my menstral cycle? 

I was taking alli for a month. after being one week late on my period I quit taking it. I have all the symptoms, bloating, craveing sweets, irritable. I'm now 2 and a half weeks late.I'm going to take a pregnancy test tomorrow. After reading this I'm very convinced that its a side effect from the alli. I aree they need to do some research on this so it can be listed as a side effect.

Sorry, I haven't read the entire thread, but I am curious, those who have been late or missed their periods, are you on birth control? I am, and I haven't noticed a difference at all.

My apologies if I'm repeating something here, but a change in your physical activity will definitely be a factor in your menstrual cycle. It could take months for your body to get use to the change. Actually, the more active you get, the shorter the cycle! There's another plus in working out!

I used to do clinical research for a pharmaceutical company in New Jersey; so, I understand the concept of side-effects.  I am a bit concerned about this issue of a missed period.

I am like clock-work, and I am now a week late.  I am not pregnant, since I don't have a boy-friend currently.  I have not significantly increased my exercise, and I have not made major changes to my diet, except to eat carrots, when I am tempted to eat a cookie for a snack.  Maybe I have eaten less of my son's mac & cheese.

If orlistat has no effect on hormones, why are some doctors testing and seeing results on PCOS treatment?  I don't have a problem with it affecting my cycle (temporarily, that is), if I knew what was going on.  Of course, such an effect could negatively impact sales, since women probably are the main users of the product, and those woman are usually of child-bearing age.  No one wants to risk taking a drug that may cause unplanned pregnancies.

 I am going to stop taking the drug until my period returns, and just keep myself on a healthy diet, which should not make my period late.  I really am concerned about what is going on.  The scientist in me may see if restarting orlistat causes my period to be late again (assuming my period returns after stopping the drug).  If my period stops again after restarting orlistat, I will be convinced there is a correlation, and I will not use or recommend the drug for any of my friends until you all explain the risk in this regard.

By the way, just because everyone who takes the drug doesn't have this SE, doesn't mean it doesn't exist.  I tested antidepressants.  Not everyone taking the medication experienced dry mouth or hypersomnia; noneless, it was a SE for those who experienced it.

Thank you for your interest in the alli program and your involvement in the community message board. alli is different because it is the only FDA-approved OTC weight loss aid. It also works in the digestive tract, does not enter the bloodstream or interact with your heart or brain. You may be experiencing your noted effects as your body adjusts to a reduced-calorie diet or increased physical activity. Make sure to eat your recommended allowance of calories throughout the day, stay hydrated and increase your physically activity level gradually. If effects continue, please see your healthcare professional.

Hi Cats-2,

Orlistat, the active ingredient in alli, works in the gut by inhibiting the enzyme lipase and thereby inhibiting the breakdown and absorption of consumed fat (about 25% with one 60mg dose). Orlistat is minimally absorbed (5%) and is excreted unchanged.  It is effective in the body for up to 2 hours.

Clinical studies have shown no effect on hormone levels or the menstrual cycle.  When compared with placebo there is no clinically significant difference. There are many  variables that have an effect on the menstrual cycle: diet, exercise, age , weight (loss or gain), stress. If it is of concern you need to consult your physician.

With PCOS, the estrogen levels are off causing irregular menstrual cycles and inability to conceive.  Since the majority of women who suffer from PCOS are overweight and estrogen has an affinity for fat cells, physicians have seen beneficial results when utilizing orlistat to aide these women in losing weight.  It is the loss of weight and fat that affects PCOS not the drug.

Hope this helps.

Sophia De Monte RPh

"To suggest that these small changes are what altered my cycle is almost insulting to my intelligence"

I'm sorry you feel insulted, but changes in your lifestyle, no matter how minimal, DOES affect your body. I noticed a huge difference when I started working out 7 years ago and again when I was laid-up and and didn't eat-right/exercise. I realize I can't convice you of that, so if you're still adament that it's the Orlistat that's actually causung you distress, the solution is to just stop taking it.

I find this discussion very interesting, to say the least.  I have experienced an irregular cycle since taking Alli.  I have been watching the board and I have researched other message boards that have gone back several years.  Some of the message boards that involve discussions about Xenical show the same kinds of concerns way before Alli came on the market.  In fact, there are many sites that list 'irregular menstrual cycles' as a side effect. 

While I appreciate that it may seem that it could be estrogen that is stored in fat, that exercise and changes in diet may cause this, I am not overweight and tried Alli to lose that last 5-7 pounds.  I have a normal amount of body fat and lost that weight at a reasonable pace.  I didn't have any SE's because I managed my fat intake well and watched what I ate.  I did not increase my activity level because I am already very active.  My hormone levels have been checked, and they are right on, so it is not peri menopause.  I know my body inside and out and am well aware when there is something amiss. 

I think Alli has great benefits, but I am concerned that this could be a potentially serious side effect and, if women are experiencing irregular cycles, I would hope that it is taken seriously.

Hello. To report the occurrence of treatment effects and/or any adverse events related to alli, you may call our customer service line at 1-800-671-2554 (M-F 9am to 9pm EST). The only way to truly collect information about a product in a very large group of users is to collect information postmarketing. If you have experienced any treatment effects, you need to report the changes.

Thank you, Maria Marzella Sulli, Pharm.D.

I am sorry for all of you who are upset about missed periods.  Personally, I would love that side effect.  I'm 50 and still have heavy bleeding for 8 to 14 days a month.  I have been through every test there is.  None of the doctors I've seen can find anything wrong.  I've tried different birth controll pills.  They help for a couple of months but then the heavy bleeding returns.  I had been hoping that alli stops or lightens my periods.  I've been taking it for a week now.  I got my period the day after I started alli and it has been heavy all week.  If I excersize while I'm bleeding, it makes it much worse.  I like to excersize, so this isn't an excuse not to excersize. I'm considering asking doctors for hysterectomy, but I don't want to miss work for that long.  My family is very dependent on my salary.

Yaz is great but you can miss your period- I was on BC for almost 11 years- from the time I was 11 y/o to the time i was 22 (almost 23) y/o and i went from having these 4-6wk long periods to 3 days on yaz. I've tried them all and its great but before you blame it on a diet pill you may want to see your gyno.  And you do understand that stressing about it does make it worse? If you are really worried about taking alli do it under dr's supervision, all your doctors, that is what i'm doing and i have no worries or concerns. I don't know how over weight or if you even are but that will change your periods and it doesn't matter that it has never happened before- that is the female body.

good luck and schedule you an appt w/ your dr.

PS: think about all the calories in the drinks- its just helping you not to consume those..hehe

 I have been taking Alli since it first came out.  Last month my period was late and lite.  It is always on time and heavy.  My husband has been fixed.  I thought maybe it was from not taking a multivitamin.