Thanks for being in touch. I understand your concern.
The recommended usage is 4 capsules/day: 2 in the morning and 2 in the afternoon. However, this may be a little too high for some users, especially if this is the first time you start taking the product. I recommend starting with half adosage until you feel that your body is OK with it. Then you may increase to the standard 4 capsules per day.
I suggest that you experiment with the dosage and stick to what works for you. The effects of Tongkat Ali accumulate gradually. However, it is important to leave a resting period to avoid your body from getting accustomed to Tongakt Ali. Ex. If you take 4 days in a row rest 2 days. The response time varies from person to person but on average I would say it takes about two weeks. Keep in mind it is important to follow the dosage regular to the most out of it. The bottle contains 80 capsule which should last you for a month.
When it comes to increasing size of the penis, I don't think supplementation will have much effect. There are some testimonials of people saying that tongkat ali can increase penis size, and I even had a couple of customers claiming that, but I do not think that penis size can be increased by taking supplements. You have a better chance by using penis stretching exercises or tools (like bathmate).
If you are looking for greater libido, endurance and better erection quality, then yes, tongkat ali may be able to help you achieve that. If you combine tongkat ali with a healthy diet and some exercise, there is a good chance to improve your sexual capability.
For your last question, Tongkat Ali is a herbal supplement and any effects any supplement can bring will disappear over time when you stop taking the supplement. The good news is, it can help you "snowball" positive change that may last.
If you have further questions or concerns just send me an email.